When Reason Isn’t Enough

As someone who routinely and vocally advocates for reason and speaks out against all forms of irrationality and faith-based beliefs, I frequently encounter the attempted counter-point that efforts at exercising reason are no guarantee for success, with my interlocutor citing numerous examples of strict adherence to the process of reason resulting in errant information and conclusions.

And it’s true. It might surprise you to hear me say this, but when investigating truth-claims and propositions, when engaged in science or forensics, when trying to ascertain what is real and what isn’t… even the strictest application of reason is no guarantee that ones conclusion will lead to the right answer.

Finding out the “truth” requires more than just an effective process. It also requires complete and correct information. That is the wild-card that limits the certainty of any conclusion made using the process of reason.

This is one reason that “proof” is a word that is typically limited to the realm of math, or math-based pursuits (such as chess). Rational skeptics do not deal in “proof”; they deal in the preponderance of the evidence. For example, I believe the moon landing happened because the evidence for it is, in my mind, convincing. However, it is possible that future discoveries may reveal the moon landing to have been a hoax. It’s not likely, but it’s possible. Therefore the moon landing is not proven… but proof is not a prerequisite for rational belief.

(Proof is possible in the realm of math because complete information is given up front, and the possible introduction of new information is not considered. For example, if you want to know what the simplest way to express 2+2 is, the answer is 4. This is easily demonstrated, and there is no possible “new” information that can change the answer. No discovery will change the answer, because the concepts are fixed by their very definition.)

Reason is a process that always works. Its ability to provide results is limited to the quality and completeness of the information at its disposal. It is vital to recognize that this is not a limitation of the process of reason, but rather a limitation of the human condition. As long as our access to information is limited, and as long as the quality of the information we do have access to is subject to imperfection, reasons ability to lead us to truth will be limited.

I once read an amusing quote from Charles Babbage, the man who originated the concept of a programmable computer. His efforts to educate to populace on the concept of a device that would take data and process it into usable information were often met by objections that resembled the very same objection we find against reason today.

“It doesn’t always produce the right answers!” – This is a vague and misguided indictment of the idea that [(a good process) + (good and complete information) = (the right answer)]. It’s vague because it doesn’t specify the point of failure, and its misguided because those who invoke it tend to believe that the failure was in reasons ability to process information rather than in the quality or completeness of the information itself. Babbage’s amusing recollections tell the story:

On two occasions I have been asked, “Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?” … I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.

It’s amusing because it was a genial way of saying “This is the stupidest f***ing question I’ve heard in my life.”, and it’s also instructive because it was the first statement expressing what would later become a computing truism: Garbage in = Garbage out.

To wit: If you are looking for the simplest way to express 2+2, then you had better punch the correct buttons on your calculator, in the correct order, if you want the correct answer. Punching any of the wrong buttons, failing to push all the correct buttons, or pushing all of the correct buttons in an incorrect sequence will cause the calculator to display something other than the correct answer. This does not mean the calculator is unreliable; on the contrary, it means that the calculator works.

And so it is with reason. Bad (or incomplete) information into the process will result in bad (or incomplete) information coming out.

Some years ago I saw a fantastic movie that illustrates the principle that reason can only provide results as reliable as the available information – “The Life of David Gale”.

You can read the plot of the movie in the Wiki article if you like, but I recommend you watch the movie. Long story short – David Gale and a co-conspirator devise a plan to prove that, no matter how certain one believes they that they have accurate and complete information, there is always the possibility that new information may be discovered that changes everything. It also speaks an important truth about how this principle applies to capital punishment (to wit: the imposition of a sentence that cannot be revoked even if exculpatory information is subsequently obtained is a bad idea).

The bottom line is that no amount of examples where incorrect or incomplete information led to incorrect or incomplete results is an indictment of the process of reason. Sometimes one doesn’t know all the relevant facts. Sometimes the information one has available is incorrect. Sometime you will accidentally punch the wrong numbers into the calculator. This means that no matter how committed one is to reason, one will be wrong from time to time. This is because the process of reason works, not because it doesn’t.

Note 1: There is another element of reason/logic required in order to obtain truth, which I have omitted from this essay for the sake of brevity – the mechanism (or machine) that is applying the process must be in good working order. If the physical parts of the brain, calculator, computer, etc… are broken or otherwise damaged, the value of the output is diminished. This is an obvious issue that few people would challenge, so for the sake of this essay I allowed for the assumption that the physical mechanism in question is in good working order.

Note 2: “The Life of David Gale” wasn’t exactly a box-office smash, but I enjoyed it and I think it speaks well to my point.